This invention relates to a toner application method for developing electrostatic latent images with a toner and magnetic particles for the toner application.
Conventionally, various types of apparatus have been proposed and put into practice as a dry type one-component developer apparatus. However, in any of those types, it has been very difficult to form a thin layer of one-component dry developer, so that a relatively thick layer of the developer is used. On the other hand, the recent desire for the improved sharpness, resolution or other qualities of developed images has necessitated the achievement of a system for forming a thin layer of one-component dry developer.
A method of forming a thin layer of one component dry developer has been proposed in Japanese Laid-Open Patent Application No. 43037/1979 and has been put into practical use. However, this method is directed to the formation of a thin layer of a magnetic developer, not of a non-magnetic developer. The particles of a magnetic developer must each contain a magnetic material in a large proportion to gain a magnetic property. This is disadvantageous since it results in poor image fixing characteristic when the developed image is heat-fixed on a recording paper to be transfer-printed. Further, because the magnetic material is generally black or dark-brown in color, it is difficult to obtain a clear color image by using a magnetic toner.